[RFC][PATCH v3 01/15] bpftool: Attempt to link static libraries

[Roberto Sassu <roberto.sassu@huawei.com>]

Introduce the BPFTOOL_STATIC make variable, to let users build bpftool with
static libraries (when set to 1). This increases the portability of the
binary, especially for testing.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 tools/bpf/bpftool/Makefile | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 4b09a5c3b9f1..4628df456245 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -98,6 +98,13 @@ FEATURE_TESTS = libbfd libbfd-liberty libbfd-liberty-z \
 FEATURE_DISPLAY = libbfd libbfd-liberty libbfd-liberty-z \
 		  disassembler-four-args libcap clang-bpf-co-re
 
+ifeq ($(BPFTOOL_STATIC),1)
+FEATURE_CHECK_LDFLAGS-libbfd = -static
+FEATURE_CHECK_LDFLAGS-libbfd-liberty = -static
+FEATURE_CHECK_LDFLAGS-libbfd-liberty-z = -static
+FEATURE_CHECK_LDFLAGS-libcap = -static
+endif
+
 check_feat := 1
 NON_CHECK_FEAT_TARGETS := clean uninstall doc doc-clean doc-install doc-uninstall
 ifdef MAKECMDGOALS
@@ -122,8 +129,12 @@ LIBS = $(LIBBPF) -lelf -lz
 LIBS_BOOTSTRAP = $(LIBBPF_BOOTSTRAP) -lelf -lz
 ifeq ($(feature-libcap), 1)
 CFLAGS += -DUSE_LIBCAP
+ifeq ($(BPFTOOL_STATIC),1)
+LIBS += -l:libcap.a
+else
 LIBS += -lcap
 endif
+endif
 
 include $(wildcard $(OUTPUT)*.d)
 
@@ -133,6 +144,16 @@ BFD_SRCS = jit_disasm.c
 
 SRCS = $(filter-out $(BFD_SRCS),$(wildcard *.c))
 
+ifeq ($(BPFTOOL_STATIC),1)
+ifeq ($(feature-libbfd),1)
+  LIBS += -l:libbfd.a -ldl -l:libopcodes.a
+else ifeq ($(feature-libbfd-liberty),1)
+  LIBS += -l:libbfd.a -ldl -l:libopcodes.a -l:libiberty.a
+else ifeq ($(feature-libbfd-liberty-z),1)
+  LIBS += -l:libbfd.a -ldl -l:libopcodes.a -l:libiberty.a -l:libz.a
+  LIBS := $(filter-out -lz, $(LIBS))
+endif
+else
 ifeq ($(feature-libbfd),1)
   LIBS += -lbfd -ldl -lopcodes
 else ifeq ($(feature-libbfd-liberty),1)
@@ -140,6 +161,7 @@ else ifeq ($(feature-libbfd-liberty),1)
 else ifeq ($(feature-libbfd-liberty-z),1)
   LIBS += -lbfd -ldl -lopcodes -liberty -lz
 endif
+endif
 
 ifneq ($(filter -lbfd,$(LIBS)),)
 CFLAGS += -DHAVE_LIBBFD_SUPPORT
-- 
2.25.1